FR2521797A1 - METHOD AND DEVICES FOR MINIMIZING INDUCED POWER IN A CONSTANT, ELECTROMAGNETICALLY CONTACTLESS CONDUCTIVE FLAT - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS AND TO DEVICES FOR IMPLEMENTING THIS PROCESS ALLOWING TO REDUCE, TO ITS MINIMUM, THE POWER INDUCED IN A FLAT PRODUCT CONDUCTIVE TO STOPPING OR RUNNING, POWER RELATED TO THE CREATION OF FORCES ELECTROMAGNETIC FOR THE PURPOSES OF HOLDING IN POSITION WITHOUT CONTACT, IN PARTICULAR BY GUIDING OR LEVITATION. A DEVICE ACCORDING TO THE INVENTION IS CHARACTERIZED IN THAT IT CONTAINS FOR EACH ZONE IN WHICH THE ELECTROMAGNETIC FORCES ARE INDUCED AT LEAST ONE PAIR OF INDUCTORS A AND B, WITH SEVERAL POLES, THE POLAR SURFACES OF WHICH ARE SENSITIVELY PARALLEL TO THE PRODUCT, THE TWO INDUCTERS OF A PAIR BEING SENSITIVELY SYMMETRICALLY ARRANGED WITH RESPECT TO THE SURFACE OF THE ZONE CORRESPONDING TO THE POSITION OF BALANCE DESIRED, THE POLES FACING TWO IN TWO ON EACH OTHER OF THE PRODUCT BE MAINTAINED AT ALL TIMES OF SAME POLARITY, THE FLOWS THROUGH THEM BEING SENSITIVELY OF THE SAME SIZE. THE INVENTION APPLIES TO CONDUCTIVE FLAT PRODUCTS HELD ELECTROMAGNETICALLY WITHOUT CONTACT.

Description

The present invention relates to a method

  and devices for implementing this method make it possible

  to reduce, to a minimum, the power induced in

  conductive flat product at a standstill or in

  related to the creation of electromagnetic forces for the purpose of maintaining contactless

guidance or levitation.

  This invention applies in particular to

  finishing procedures such as heat treatments and, in general, whenever it is necessary to move or

  maintain products without contact and without heating.

  The known methods and devices for moving

  cementing or non-contact holding of flat products

  ductors by means of electromagnetic forces present

  the disadvantage of causing a significant heating.

  They generally comprise a single inductor disposed under the product to be moved or maintained without contact (see FIG. 1 of the attached drawings), the intensity and the frequency of the magnetic field being adapted to the characteristics

  physical and product dimensions.

  The method, which is the subject of the present invention, makes it possible to considerably reduce the heating induced in a

  conductive flat product when stationary or in motion, heating

  the creation of electromagnetic forces for the purpose of maintaining contactless

guidance or levitation.

  This process consists in opposing in certain zones

  flat product and perpendicular to the corresponding surface.

  of these, two substantially equivalent alternative magnetic fluxes so that in each of these

  zones, the product being in an equilibrium position, the composition

  of the resulting field perpendicular to each zone is minimal and that the components parallel to each zone

  maximum, thanks to a deviation of the two flows.

  A device for implementing the method

  essentially for each zone in which

  electromagnetic forces at least one pair of

  multi-pole conductors whose polar surfaces are substantially parallel to the product, the two inductors of the pair being arranged substantially symmetrically

  relative to the area of the zone corresponding to the posi-

  tion of equilibrium sought, the poles facing each other in pairs on either side of the product are maintained at all times with the same polarity, the flows passing through them being

substantially of the same size.

  In an embodiment particularly well adapted but not exclusively to a tape treatment,

  each of the inductors consists of successive poles

  sifs of elongated form which are alternately North and South

at a given moment.

  In another particular embodiment

  Although well suited, but not exclusively, to a sheet or plate treatment, each of the inductors consists of identical poles arranged regularly in the same polar pitch in two orthogonal directions. In each of these directions, at each instant, the successive poles are

alternately North and South.

  Other features and benefits of the

  present invention will emerge from the description which will

  follow with reference to the attached drawings in which

  FIG. 1 is an elevational view of a

  known positive electromagnetic levitation conductive flat products comprising a single inductor disposed under the product to levitate;

  FIG. 2 is an elevational view of a device

  sitive, according to the invention, electromagnetic levitation conductive flat products; Figure 3 is a plan view of an embodiment of one of the two inductors of a device according to the invention, adapted to a strip processing; and FIG. 4 is a plan view of one embodiment of one of the two inductors of a device according to the invention, suitable for processing sheets or plates. In the embodiment shown in FIG. 2, a device for electromagnetic levitation of

  conductive flat products consists of a pair of

  substantially identical horizontal conductors (A) and (B) facing each other, arranged on either side of the product (P) and having a plurality of poles, successively North and South at a given instant. The two adjacent identical poles are at all times of the same polarity.

  The two alternative magnetic fluxes

  equivalent in the area of levitation.

  of the product are opposite and thus mutually deviating, the component of the resulting field which is perpendicular to the product is minimal whereas the components parallel to the

product are maximum.

  In the embodiment of the invention,

  shown in Figure 3, more particularly but not excluded

  adapted to band processing, each of the induc-

  tors is constituted by successive poles (1) of elongated shape which are successively North and South at a given instant. In the embodiment, of which FIG. 4 is a special case, adapted more particularly but not exclusively to a sheet or plate treatment, each of the inductors consists of several identical poles (2> whose principal dimensions of the section are of the same order of magnitude, arranged regularly in two different directions In each of these directions, the consecutive poles are successively North and South, at a

given moment.

  Of course, the invention applies in the case where it is desired to create forces of different intensities according to the zones of the product, by adjustments independent of the magnitude of the fluxes in each of these zones, for example to maintain in position products subject to jets

  various fluids or gravity.

  From the embodiments described above,

  previously, one easily deduces configurations of

  whose geometry of the polar surfaces are adapted to products whose surface is not necessarily flat,

  for example, curved, cylindrical or corrugated.

  In addition, action areas may concern

all or part of the product.

  Previous devices have been described with use of single-phase current, but devices using polyphase currents also enter

the scope of the invention.

  Finally, it should be understood that the present invention has been described and shown only as a preferred example and that it will be possible to provide equivalences in its constituent elements without, for all that, exiting

of the scope of the invention.

Claims (6)

  A method for minimizing the induced power in a conductive flat product when stationary or in motion, power related to the creation of electromagnetic forces for maintaining a position in contactless position, characterized in that opposing in certain areas of the product and   perpendicular to the corresponding surface of those   here, two alternating magnetic fluxes substantially equivalent   so that in each of these areas the product   being in equilibrium position, the resulting field component   perpendicular to each zone is minimal and that the components parallel to each zone are maximal thanks to to a deviation of the two flows.   2 Device for minimizing the induced power in a conductive flat product, according to the process of claim 1, characterized in that it comprises for each zone in which the electromagnetic forces are induced at least one pair of inductors, several pale, whose polar surfaces are substantially parallel to the product, the two inductors of the pair being arranged so   substantially symmetrical with respect to the surface of the area.   corresponding to the position of equilibrium sought, the poles facing each other in pairs on both sides of the product being maintained at all times with the same polarity, the   flow therethrough being of substantially the same size.   3 Device according to claim 2, characterized   characterized in that the flux quantities of each pair of inductors acting on the different zones are independently adjustable to obtain intensity forces   in each of the corresponding areas of the   Duit. 4 Device for minimizing induced power   in a conductive flat product in electromagnetic levitation   tick, according to claim 2, characterized in that it consists of at least one pair of substantially identical horizontal inductors (A) and (B), arranged on both sides.   of the product (P), the successive poles being alternating   North and South at a given moment.   Device according to any one of Claims 2 to 4, characterized in that each of the inductors   consists of elongated poles (1), the   positive being then more particularly but not exclusively   suitable for the treatment of strip products.   6 Device according to any one of the   2 to 4, characterized in that each of the inductors   consists of poles (2) whose main dimensions   blades of the section are of the same order of magnitude, arranged regularly in two different directions, the device then being more particularly but not exclusively   suitable for the processing of plate products.   Device according to claim 2, characterized   characterized in that the geometry of the pole surfaces of the inductor pairs is adapted to curved surface products.   8 Device according to claim 2, characterized   in that the zones in which the   electromagnetic forces constitute the whole of the Duit.